/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde licenses this file to you under the Apache License,
// Version 2.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at:
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 */
package org.olap4j.mdx;

import org.olap4j.type.Type;

import java.io.PrintWriter;

/**
 * A parameter to an MDX query.
 * 
 * <p>
 * Not all dialects of MDX support parameters. If a dialect supports parameters, the driver for that dialect should
 * extend the parser to introduce a ParameterNode into the parse tree wherever a parameter is encountered.
 * 
 * <p>
 * For example, in Mondrian's dialect of MDX, a call to the <code>Param(name,
 * type, defaultValueExpr)</code> function introduces a parameter, and <code>ParamRef(name)</code> creates a reference
 * to a parameter defined elsewhere in the query.
 */
public class ParameterNode implements ParseTreeNode {
	private String name;
	private Type type;
	private ParseTreeNode defaultValueExpression;
	private final ParseRegion region;

	/**
	 * Creates a ParameterNode.
	 * 
	 * <p>
	 * The <code>name</code> must not be null, and the <code>defaultValueExpression</code> must be consistent with the
	 * <code>type</code>.
	 * 
	 * @param region
	 *            Region of source code
	 * @param name
	 *            Name of parameter
	 * @param type
	 *            Type of parameter
	 * @param defaultValueExpression
	 *            Expression which yields the default value of the parameter
	 */
	public ParameterNode(ParseRegion region, String name, Type type, ParseTreeNode defaultValueExpression) {
		assert name != null;
		assert type != null;
		assert defaultValueExpression != null;
		this.region = region;
		this.name = name;
		this.type = type;
		this.defaultValueExpression = defaultValueExpression;
	}

	public ParseRegion getRegion() {
		return region;
	}

	public <T> T accept(ParseTreeVisitor<T> visitor) {
		final T t = visitor.visit(this);
		defaultValueExpression.accept(visitor);
		return t;
	}

	public void unparse(ParseTreeWriter writer) {
		PrintWriter pw = writer.getPrintWriter();
		pw.print("Param(");
		pw.print(MdxUtil.quoteForMdx(name));
		pw.print(", ");
		pw.print(type);
		pw.print(", ");
		defaultValueExpression.unparse(writer);
		pw.print(")");
	}

	public Type getType() {
		// not an expression
		return null;
	}

	/**
	 * Returns the name of this parameter.
	 * 
	 * @return name of this parameter
	 */
	public String getName() {
		return name;
	}

	/**
	 * Sets the name of this parameter.
	 * 
	 * @param name
	 *            Parameter name
	 */
	public void setName(String name) {
		this.name = name;
	}

	/**
	 * Sets the type of this parameter.
	 * 
	 * @param type
	 *            Type
	 */
	public void setType(Type type) {
		this.type = type;
	}

	/**
	 * Returns the expression which yields the default value of this parameter.
	 * 
	 * @return expression which yields the default value of this parameter
	 */
	public ParseTreeNode getDefaultValueExpression() {
		return defaultValueExpression;
	}

	/**
	 * Sets the expression which yields the default value of this parameter.
	 * 
	 * @param defaultValueExpression
	 *            default value expression
	 */
	public void setDefaultValueExpression(ParseTreeNode defaultValueExpression) {
		this.defaultValueExpression = defaultValueExpression;
	}

	public ParameterNode deepCopy() {
		return new ParameterNode(this.region, this.name, this.type, // types are immutable
				this.defaultValueExpression.deepCopy());
	}
}

// End ParameterNode.java
